Dr. Vladislav Zlatinov
Central Vet Clinic – Sofia
Synovial cell sarcoma is the most common joint tumor in dogs. It is a malignant neoplasm arising from mesenchymal cells outside the synovial membrane of joints and bursas1 . In dogs, synovial cell sarcomas usually occur in large breeds, with a predisposition for flat-coated and golden retrievers1,2 . Middle-aged dogs are most commonly affected, and there is no sex predilection. Synovial cell sarcomas usually involve the larger joints, but any joint can be affected.
Other joint tumors reported in dogs include fibrosarcoma, myxoma, malignant giant cell tumor of soft tissue and others. Recently, histiocytic sarcomas have been reported in the periarticular tissue of large appendicular joints3 .
Synovial cell sarcomas are locally aggressive with a moderate-to-high metastatic potential, depending on histologic grade. The average survival time with SCS is around 30 months, which is significantly better prognosis compared to the most common canine neoplasia- osteosarcoma.
Limb amputation is recommended for treatment of the SCS tumor because local recurrence is significantly lower compared to marginal resection.
In the recent years, an amputation alternative- limb sparing procedure, was developed. The first animal case (2008) with integrated prosthesis included bilateral tibial stem implantation4. The more recent procedure ITAP (Integrated Tanscutaneous Amputee Prosthesis)-Stanmore Implants Worldwide Ltd, UK, is demanding technique that consists of low limb amputation and metal stem medullary canal insertion, aiming long term bone-implant integration. Suggested period for this integration has been suggested to be 6 weeks5. This is the most vulnerable period that demands high degree of implant stability, allowing bone tissue ingrowth into the implant micropores. Once stable implant- stem fixation occurs, an external limb prosthesis attachment gives the opportunity for weight baring and some degree of limb functional recovery.
This case report presents the short term functional result after application of ITAP technique in a five years old golden retriever. The dog’s tarsal joint was affected by synovial sarcoma. Custom manufactured implant with rigid locking plate fixation was developed. The goal of the implant design was solid fixation allowance of immediate weight baring, even before the stem integration. The follow up period of the case is 3 months post operatively. The patient revealed very good pain free limb function, starting almost immediately after the amputation.
A 5 years old male Golden retriever dog, weighting 39 kg was presented at Central Vet Clinic – Sofia. The owner reported low grade lameness with the left hind leg, lasting for more than one month and badly responding to NSAIDs.
We did a thorough clinical exam, revealing normal over-all condition, moderate obese body score, choleric temperament. We found mild (II/IV) left hind leg weight baring lameness. Thickening of the left hock joint was noticed. Mildy decreased ROM with mild pain were appreciated in the affected joint.
Orthogonal radiographs of the left hock revealed diffuse intrinsic joint swelling. We found aggressive bone lysis areas (mostly severe at distal fibula) and moderate aggressive periosteal reaction (mostly affecting the tarsal bones). No abnormalities were detected on preoperative 3-view thoracic radiographs, abdominal ultrasound, echocardiography, and blood tests.
Fine- needle aspirates were taken. Cytology revealed numerous clusters of plump, oval to spindloid cells often with moderate cellular atypia. Considering this , the signalment and the imaging findings, a diagnosis of joint sarcoma was suggested.
A decision for limb sparing surgery by low trans-tibial amputation and integrated limb prosthesis (ITAP) was made.
Implant planing and manufacturing
A custom-made ITAP implant was manufactured using CNC machinery with additional welding process. Medical titanium (grade 4) was used for the production. The implant desired shape and size of the was predetermined using only radiographs. The straight shape and straight medullary canal made the design simple enough, so no necessity for computer tomography imaging and planning was found. The ITAP implant components included a 7 mm (rough surface) intramedulary stem, 3, 5 mm locking plate part, drilled titanium collar (flange) and most distally smooth 8 mm titanium rod (outside part). Locking 4 mm screws were produced corresponding to the plate locking mechanism.
A custom made exoprostheis was manufactured using combination of plastic polymer, rubber and metal elements. The length was conformed (with mild underestimation) to the natural foot size. Angulation of 135 degree of was planned to mimic the natural hock joint position. Shock absorbing (spring) design was developed.
The titanium flange role is the reduction of epithelial downgrowth and good soft-tissue integration.
Premedication with Medetomidine and Butorphanol was used, followed by Propofol induction. The maintenance was sustained by Isoflurane and Ketamin drop in the fluid sack. Epidural block with Ropivacaine was provided just before the surgery.
Cimicoxib (Cimalgex) was prescribed for 7 days post op. No opioids were used in the recovery period.
For the surgical intervention, the dog was positioned in dorsal recumbency. After macroscopic evaluation, transverse sharp dissection of soft tissues, covering the distal tibial dyapihis was done. Four centimetres distance proximally from the edge of the tarsal lump was aimed. Muscles tendons (including common calcaneal tendon) were severed. A strict haemostasis by electrocautery and ligation of the main blood vessels was achieved. Minimally invasive approach (bone tunnelling) was used for the insertion of the plate element under the soft tissue on the medial side. Mild contouring of the proximal plate part was needed to fit the tibia shape. No canal drilling was needed- the stem part was impacted quite easily into the soft bone marrow tissue. Gentle axial hammering ensured good bone to flange contact.
Muscle tendons and crural fascia free ends were sutured to the special designed flange holes. After gentle subcutaneous fat debridement the skin edges were sutured over the flange surface. Special attention was emphasised so the circular skin defect was closed with an “appropriate” tension- no skin abundance, but also with no excessive tension on the stitches.
Immediate post op care
Preventive antibiotic therapy (Amoxcillin calvulonic acid) and NSAIDs (Cimalgex) was prescribed for 7 days
A Modified Robert Jones bandage was applied over the amputee stump. The bandage was removed after three days and the exoprosthesis was attached, with similar soft bandage applied around the stump.
Strict cage rest with very short leash walks was emphasised in the immediate post op period.
A recheck radiograph at six weeks post op demonstrated solidly homogenous bone-implant contact area, suggesting osteointegration in process.
“Moderate differentiated synovial cell sarcoma.”
Atypical spindle shaped cells with indistinct borders and variable amounts of eosinophilic fibrillar cytoplasm and stroma. The long term prognosis is good but still variable.
The dog revealed very good comfort after the procedure, with immediate weight baring. Light protective bandage was used to cover the distal stump area and prosthesis for two months post op. The followed period (within 3 months) revealed very fast and pain free limb usage with milld lameness (II/V)
Leash walk 6 day post op.
Going for a walk 14 day post op.
2 months post op
3 months post op
Locking plate ITAP design can provide adequate stability needed for implant osteointegration, while early limb usage is allowed. The role of shock absorbing exoprosthesis for success is unclear. This fast functional recovery can make the ITAP procedure more attractive and better accepted by the owners of pets that need similar limb sparing surgeries. Further investigations may demonstrate ITAP complications variabilities (ratio) and long term results.
Hind limb preservation surgery in a cat using customised 3D printed expandable arthrodesis plate – case report
United Veterinary Clinic, 34 Tzarevetz street, Varna, Bulgaria
The aim of this case report is to describe the technique and clinical outcome of limb salvage procedure in a cat with а distal segmental femoral bone deficit due to bone nonunion using customised expandable stifle arthrodesis plate.
3.5 years old female cat was presented to us after unsuccessful repair of multiple fractures of the right femur. The current condition of the cat was as follow: Gustilo-Anderson type 3b open intercondylar and distal diaphyseal femoral fracture, fracture of the femoral head, fracture of the greater trochanter, patella ligament rupture and extensive skin and soft tissue loss in the right stifle region (1). The aim of the treatment was anatomical reconstruction of the femoral fractures, temporary transarticular fixation and soft tissue reconstruction using ipsilateral mammary chain (caudal superficial epigastric axial pattern flap) with a future plan of performing stifle arthrodesis due to a non repairable patella tendon rupture (2). Surgical goal was achieved, but sequestration of the whole distal femoral segment was confirmed radiographically two and a half months after the revision surgery. As the owner declined amputation and insisted for limb salvage procedure, personalised 3D expandable arthrodesis plate was designed, fabricated and used for achieving stifle arthrodesis.
Two radiographic examinations immediately postoperatively and five months after surgery were performed. Four months follow up x-rays showed no signs of periprosthetic bone resorption which seems to be in the main concern in this clinical case and whether the porous spacer will be integrated to both the femur and the tibia.
Designing and fabrication of the customised implant is a complex, time consuming and cost depending process, but 3D printed expandable stifle arthrodesis plate could be a realistic option for hind limb preservation in cats. Further cases and long term follow up are required to determine the success and complication risk of the procedure.
The femur is the most commonly fractured bone in cats, accounting for more than 30% of feline fractures (3). Those involving the shaft and the distal femur are most commonly seen. Inadequate fracture fixation leads to poor mechanical stability and further compromise of the biological environment, especially if there are migrating implants. The basic tenets for treatment of joint fractures are reestablishment of articular congruity, joint stability, axial alignment and preservation of joint mobility (4). Patella tendon rupture is unusual condition and it is most commonly due to a sharp trauma (5). In our case, an iatrogenic rupture of the patella tendon was suspected due to migrating implants following surgical stabilisation of the distal femur fracture. Arthrodesis of the stifle joint is a salvage treatment option if joint function cannot be preserved with another methods. Arthrodesis will leave the cat with significant gait alterations, and careful consideration should be made before electing for this option. The angle of fusion is estimated from the standing angle of the contralateral limb, and is around 110°. Strict attention should be paid to surgical technique to avoid complications. These tend to occur because of the long lever arm created, which can result in fracture of the femur or tibia at the implant–bone junction. Implants should end in metaphyseal areas and not over the narrowest part of the diaphysis to avoid this complication (6).
3.5 years spayed female cat was presented to us after unsuccessful repair of multiple fractures of the right femur. After removal of the existing implants, reconstruction of the articular fracture was performed using 2.4mm lag screw and antirotational K-wire. 2.0 mm SOP plate was applied as medial transarticular stabilising implant and for fixation of the supracondylar fracture of the femur. Two K-wires and tension band wire were used for fixation of the greater trochanter. The femoral head seemed already stable and no attempt for surgical stabilisation was performed.
Bacterial culture was done during the first surgery and the results came back as Methicillin-resistant staphylococcus. Based on antibiotic susceptibility testing, Amikacin was used as an appropriate antibiotic for seven days. Unfortunately no signs of fracture healing were noticed in the next 8 weeks and small fistulous tract appeared at the lateral aspect of the stifle joint.
In a subsequent surgery all implants were removed together with the distal femoral fragment, a transarticular external skeletal fixator was applied and CT was performed immediately after that. Bacterial culture has been obtained and came back again positive for Methicillin-resistant staphilococcus. Chloramphenicol was initiated for 7 days p.o. based on bacterial sensitivity testing.
A further attempt was initiated for designing and producing of expandable stifle arthrodesis plate. The aim of the proposed implant was to provide stifle arthrodesis but at the same time to replace the distal femoral segment for overall limb length preservation. The implant was designed by CABIOMEDE Vet, Poland and consisted of two solid portions with locking screw holes and central porous portion for promoting bone ingrowth. The length of the porous part of the plate was 28mm and was intended to replace the missing distal femoral segment.
Two DCP holes were designed at both sides of the solid part of the plate in order to provide compression on the osteotomised bone segments against the porous part of the plate. The rest of the plate holes were locking ones and were arranged in such a way so they can engage each bones in a different angle providing some sort of orthogonal fixation and at the same time avoiding the holes form the existing ESF pins. The plate was designed to span almost the entire length of both the femur and the tibia, avoiding possible periprosthetic fracture. Limited contact under-plate surface was designed, reducing the implant footprint on the bone because of the concern of too much implant wrapping and possible implant-associated infection. The customised implant and dedicated cutting guides were printed from Polygon Medical Engineering, Russia.
During the surgery, the patient was positioned in a lateral recumbency with the affected limb upermost and cranial skin incision was performed starting from the most proximal aspect of the femur to the the most distal aspect of the tibia. A standard lateral approach to the femur was made which continued over the cranial aspect of the stifle area and on the craniomedial aspect of the tibia. The cutting guides were secured and the bone ends were osteotomised. The plate was then attached to the cranial aspect of the tibia and the femur using temporary K-wires through dedicated holes. The most distal tibial plate hole and the most proximal femoral one were designed for 2.0mm non locking cortical screw to be inserted in a neutral position and two gliding holes at both sides of the porous part of the plate for 2.4mm cortical screws in a compression mode. Autogenous cancellous bone graft was obtained from the proximal aspect of the contralateral humerus and applied at both sides of the porous part of the plate. All needed 2.4mm locking screws were predetermined and their length marked on the plate for faster and precise application.
This case report describes fracture complications in a feline femur multiple fracture and application of customised 3D printed expandable plate for stifle arthrodesis as a limb salvage procedure. The customised plate made of Titanium alloy has the features of the replacement of missing bone, providing initial fixation using screws (both non-locking and locking ones) and long-term bone fixation (bone ingrowth) (7). Our main concern was mainly the long-term bone ingrowth and the bending and shear strength of the plate at the porous/solid part of the implant. Five months after the surgery (at the time of this article has been published) there are positive radiographic signs for osteointegration (no signs of peri-implant bone osteolysis, lack of osteolysis around the screws and progressive bone bridging over the porous part of the plate). In a recent paper (8), porous implants without hydroxyapatite coating showed a consistent bone ingrowth in a canine transcortical model. Despite the concern of poor functional limb after limb sparing/fuse of the stifle joint (4) , our cat was performing extremely well and almost fully weight-bearing on the operated leg about ten days after surgery. Till today she improved her gait a lot and the limb use while she is running and playing with toys.
“Shirley is doing great. She really behaves as a kitten which never had an issue with that leg” – Shirley’s owner, 25.09.2020
2 weeks after the surgery:
- Kim P.H, Leopold S.S. Gustilo-Anderson classification. Clinical Orthopaedics and Related Research 2012, 470:3270-3274
- Moors, A. Axial pattern flaps. In: BSAVA Manual of Canine and Feline Wound Management and Reconstruction. BSAVA: 2009; 100 – 111
- Hill, F.W.G. A survey of bone fractures in the cat. J.Small Animal Practice 1977, 18, 457-463
- DeCamp C.E, Johnston A.Spencer et al. Principles of joint surgery. In: Handbook of small animal orthopedics and fracture repair. Elsevier, Inc. 2016; 211-229
- Das S., Langley-Hobbs S., et al. Patellar ligament rupture in the cat: repair methods and patient outcomes in seven cases. Journal of Feline Medicine and Surgery 2015, Vol. 17(4) 348-352
- Voss K, Langley-Hobbs S.J, Montavon P.M. Stifle joint. In: Feline Orthopaedic Surgery and Musculoskeletal Disease. Philadelphia, PA: Saunders Limited: 2009: 475-4907.
- Harrysson Ola L.A., Marcellin-Little D. et al. Applications of metal additive manufacturing in veterinary orthopaedic surgery. JOM, Vol 67, No3, 2015
- Tanzer M, Chuang P.J., et al. Characterization of bone ingrowth and interface mechanics of a new porous 3D printed biomaterial. Bone & Joint Journal 2019;101-B, 62-67
Veterinary Clinics Dobro Hrumvane
Glioblastoma is a malignant tumor of the nervous tissue. This is the fourth degree of astrocytoma. It is more common in the frontal and temporal lobes. Good contrast enhancement in magnetic resonance imaging, edema of the surrounding tissue is often observed. Macroscopically, it has well-defined borders.
Male dog, named Jazz, 9 years old, husky, brought to the clinic on 01.07.2020
There is worsening of the condition since the day before, the animal was no longer interested in food or water, there was lack of coordination. The clinical examination reveals that the animal was obtunded, but still responsive and it was responding to commands, given by the owners, it was also consciously resisting some tests, during the examination, which it doesn’t seem to like. No evidence of seizures. Posture – head turn to the left and tilt to the right. Gait – vestibular ataxia. Cranial nerves – absent menace reaction on the left. Postural reactions – decreased proprioception of the left pelvic limb, decreased hopping reaction of the right thoracic limb. Spinal reflexes – normal. Localization – the decreased proprioception only on the left pelvic limbs cannot definitively determine the localization. Due to the left head turn, the localization is determined in the left forebrain or peripheral vestibular syndrome. Differential diagnoses: ischemia, metabolic disease, neoplasia. MRI is recommended.
On 02.07.2020 blood was taken for CBC – nothing remarkable, Biochemistry – a slight increase in glucose and AST, ALP – 455.99 (10.6-109 U / L). FT4 and TSH are normal.
On 03.07.2020, an MRI was performed. The imagining showed a mass in the left cerebellum, with mass effect on the brainstem and cerebellum, obstruction of the normal outflow of cerebrospinal fluid and for that causing hydrocephalus. Also edema in the surrounding tissue.
Preoperative preparation was started with Mannitol 1.5 g/kg/12h i.v., Methylprednisolon 15.78 mg/12h i.v. Antibiotic therapy – Ceftriaxone – 1 g/12h i.v.
On July 4, 2020, a left suboccipital craniectomy was performed for removing the mass, part of which was sent for histopathology to Laboklin, Germany. Part of the capsule of the tumor has not been removed due to adhesions with the brainstem and the risk of injury during the process of removing it. An artificial dura was placed on the defect to prevent the leakage of cerebrospinal fluid.
After the surgery Jazz was recovering very well. There was a manifestation of vertical nystagmus, which disappeared quickly by itself. Antibiotic therapy was continued, as well as mannitol and methylprednisolone therapy 24 hours after the surgery. Meloxicam was included for pain management 12 hours after the steroids were stopped
The first day after the surgery Jazz was still slightly uncoordinated and his head was still with negligible turn, but he was able to get up and walk on his own.
On July 6, 2020, 48 hours after the surgery, Jazz was more stable, progressively getting better and eating and drinking water.
On July 9, 2020, in the middle of the day Jazz’s condition got worse. He started to turn his head to the left again. On the same day, the histology result was received:
Glioblastoma with high degree of malignancy.
On 10.07.2020, steroid therapy was started, which led to a fast improvement. On the next day Jazz was sent home with home therapy of prednisolone 0.5mg/kg/12h.
Consultation with oncology department for chemotherapy was recommended
On 17.07.20 the sutures were removed from the skin incision, Jazz’s therapy with prednisolone (0.5 mg/kg /12h) was continued. There was a slight incoordination and tilt of the head.
This year the created 5 years ago by our team new orthopedic technique for cases with radial nerve palsy in cats (see article http://balkanvets.com/index.php/2019/03/09/main-topic-a-new-approach-to-radial-nerve-palsy-in-cats-clinical-case-series-report/) met its biggest possibe challenge and led the case to unexpected 100 % success:
Cat, M, approx 3 years old, Otelo. The cat has survived after severe trauma which forced colleagues to amputate one front limb and to try saving the other one using standard surgical procedure. Weeks later the cat came to us for euthanasia: lethargic, anorhexic, with decubital wounds and with very deep and extremely inflammated and painful exhoriation at the chest area due to body dragging on the floors. The not amputated leg wasn’t functional. It was swallowed, with severe purulent inflammation and permanent fistula, with evaluating maluinon (high degree rotation and mild varus) and with radial nerve paralysis, the antebrachial bones showed all radiographic signes of osteomyelitis. The patient showed all clinical and paraclinical signs of evaluating sepsis. Additionally Otelo had also severe lungs problem. We took the risk to prepare the cat for the DH arthrodesis surgery and to test our technique in these extremest possible conditions.
It took almost 3 weeks to prepare Otelo fur surgery, lungs multimodal treatment including Opti-Airwei, treatment against the systemic and local infections and lesions, chronic pain and exhaustion.
We used the technique on its standard way, we just decreased the rerotation angle from 90-95 degrees to 80-82 degrees, because cats with only one front limb move the existing one to the median body line which leads to natural 10-12 degrees carpal rerotation.
Pre- and intra-operatively we took material for bacterial identification and antibiogram. Of course we counted as usual on VetDiaLab with their unique system for automathic identification even to subtype and for authomatic machine antibiograms. The VetDiaLab fantastic work was the key for complete solving of the chronic multi-infection.
Thanks to the precise lab results, the reliable technique and the amazing post-op care of our team (even including adoption of the patient by “fallen in love” with him team member) Otelo overcame the victim pose, the decubital wounds, the chest deep exhoriation and uses its leg with full geometrical functionality. The deep antebrachial bone infection was 100 % overcome only after removing one of the screws which kept infection – after this manipulation the operative suture finally healed 100 % and we removed the collar on Christmas!
Otelo Christmas video:
Every cat knee arthrodesis is an orthopedic challenge. Cats have relatively long bones, crista tibia is narrow and even sharp most cranially, and they are very active animals with common post-op serious vertical efforts, for example jumping to and from furnitures and even refrigerators. The arthrodesis of their knees requires maximal stability of the fixation, freedom for intraoperatively estimation for usage of different screws on one and the same plate – from 2.0 mm to 2.7 mm thick, a serious attention to the fixation of the plate to crista tibiae and the underlying tibia. And, of course, maximal level of aseptic and antiseptic procedures and algorithms: by every orthopedic surgery the possibility for post-op infection is proportional to the implants surface in sq mm and during arthrodesis we use wide and thick plate with serious surface and many screws sometimes even wires with serious surface too.
During the last 16 years we passed through different variations of the arthrodesis technique with different implants systems – at the beginning non-locking, later locking. Fortunately finally we found not only the best for us technique variant but also the most reliable for us implanst system and achieved constantly excellent results in 9 cats.
All 9 surgeries were very smilar with approximately equal percentage of covering of femurs as well of tibias. By all of them we used one and the same system – Mikromed locking 2.4 with one and the same plate – symmetrical limited contact straigth locking plate with “bridging” area in the middle (without hole for screw). In all 9 cases this bridging segment was positioned in the area of the femuro-tibial connection. In all cases we used on one and the same plate different screws – locking Mikromed 2.4 mm (in the tibia) and 2.7 mm (in the femur and in the bigger cats in the tibia as well) and non-locking (2.0 mm, 2.4 mm and 2.7 mm). In all cases before the tibial plating we took away with Rounger curette the most cranial 1-3 mm wide part of crista tibiae which procedure should be made very carefully and doesn’t compromise the fixation because in cats crista tibiae is build by bone compacta more caudally in comparison to dogs (that why we recommend in case of transposition of crista tibiae to cut the osteotomy into the tibia as caudal as possible – of course not damaging the menisci – in order not to compromise the healing process; but this is another story for another technique).
The patients and their individual stories before the surgery were not similar, however the results were equal: constatnly 100 % excellent. Here we present two different cases: Cat Gosho, under 4 kg, allowing manipulations without problems, with trauma not more than 2 weeks before the surgery, without muscle atrophy; and Cat Aksel, over 6 kg, very difficult to be manipulated and with “specific” temperament, which trauma happened before approx 2 years and as result the patients leg had severe muscle atrophy and weakness of the ahilea tendon.
The only difference in the approaches to both patients was the fact that because of the weight and the temperament of Aksel we left both situational wires in comparison to the surgery of Gosho where we removed them after finishing the plating process.
As in all orthopedic surgeries in cats we do not loose intra-operatively time for plate bending – more time means bigger risk of anesthetic problems and infection. We have a big collection of cat bones (cat bones are very similar, the dog bones aren’t) from cats of different weight including “arthrodesed” femur+tibia combinations. We use these models before autoclaving the implants for perfect contouring the plate to the bones and bnes combinations and for preparation of the perfect screws combination.
We recommend the dynamic compressive screw to be not in the femur but in the tibia this means to fix the plate with locking screws first to the femur and after that to start fixing it to the tibia. We recommend two non-locking 2.0 mm cross-screws in both holes nearest to the plate middle. We strongly recommend to take off the most cranial 1-3 mm slice of the tibial (crista tibiae) silhouette with Rounger for better contact between plate and bone and respectively best stability. And, of course, do not forget to take off all the cartilages, menisci, cruciate ligaments and the patella and to compress tibia to femur as strong as possible.
The nine cases prove that there is not any need of longer plates covering bigger percent of the femural and tibial length. We monitored all the 9 cats for period between 2y4m to 1 m after the procedure and there aren’t any signs of problems including fissures or fractures of bones at the plate edges.
Video of Gosho 10 m post-op:
As usually the goal is the patient to start using the leg very soon. In the first 2-5 weeks some hyperextensy of the hook and abduction of the leg are normal.
Cat Aksel 96h post-op:
Conclusion: the presented at the X-ray pictures below variant of cat knee arthrodesis with lockig system Mikromed 2.4 guarantees constantly excellent result.
Gosho X-Ray pictures:
Aksel X-Ray pictures:
Hypothyroidism endocrine disease that can be reason for very different neurological signs, varying from signs of polyradiculoneuritis to neurological signs from the brain and vestibular disorder.
The good news are that all of this neurological problems and deficits can be reverse with adequate treatment, good nursing and physiotherapy.
I will present 2 cases of hypothyroidism in dogs with very different neurological signs. In first case I did not believe that this disease can manifest so heavy clinical signs. In second case, I took blood sample for fT4 just to be sure that this is not hypothyroidism.
Signalment: Dog, F, 9 y.o., Samoyed
History: Two days ago while the dog is on a walk, the owner noticed small paresis with front legs but it was for few minutes and they went back home. The dog came in the clinic on 1st of December in lateral recumbency, not able to stand up and not able to stay on her legs, even with help. The dog could not eat without help and holding the head and the body.
General examination: no abnormalities, the dog was not vaccinated the last year. Orthopedic examination: no abnormalities.
-Hands off exam:
- Consciousness – normal
- Behavior – can’t find any abnormalities in this position
- Seizers – no seizers
- Body posture – lateral recumbency but the dog can move head and neck
- Gait – symmetrical tetraplegia
-Hands on exam:
- Cranial nerves – no neurological deficits
- Postural reaction – can’t be checked in this position
- Spinal reflexes – absent withdrawal reflex on both front legs, reduced extensor carpi radialis on the right front leg, there are no abnormalities in hind limbs spinal reflexes. Normal tail movement, there is a perineal reflex and normal deep pain sensation.
Localization: C6 – Th2
Differential diagnosis: Degenerative/Neoplastic/Vascular
At this point we were unable to make CT or MRI and the decision was to use steroids in dose 2 mg/kg, famotidine 0,5 mg/kg/12 h p.o., Omeprazole 1 mg/kg/24 h p.o. and to see what will happen on the next day. On the next day the dog was in the same condition and I repeat the steroid. After second injection the dog has profuse diarrhea so we stopped the steroid and treated the GI signs.
Two days later we made CT and there are no abnormalities.
On the next day was taken blood sample for biochemistry and fT4. The biochemistry showed no specific abnormalities, but fT4 was very low.
fT4 – 0,1 pmol/L (7,7 – 47,60 pmol/L)
Creatinin – 39 mmol/L (44,3 – 138,4 mmol/L)
Glucose – 6,2 mmol/L (3,4 – 6,00 mmol/L)
Creatin kinase – 298,1 U/L (13,7 – 119,7 U/L)
LDH – 576,9 U/L (24,1 – 219,2 U/L)
Magnesium – 2,00 mmol/L (0,7 – 1,1 mmol/L)
The algorithm was to start levothyroxine and if we don’t have any results may be the reason for this condition is polyradiculoneurtis.
I didn’t believe that the reason for so hard clinical signs is only hypothyroidism.
Eight days later the dog was with total areflexion of all four limbs.
The decision was to take CSF, muscle biopsy (from M. gastrocnemius, M. triceps brachii) and nerve biopsy (from n. peroneus). The samples (the biopsies and the CSF smear) were send to Laboklin Germany. The cells count, protein, glucose and microbiology of CSF were made in laboratory department of “Dobro hrumvane!” veterinary clinics.
The results were:
Number of cells – normal (<5)
Protein total – 2.4 (<25)
Glucose – 4.6 (80% of normal blood values)
Microbiology – negative
“The smears were cell free. Only few keratin flakes were present.
– striated muscle with multifocal mild degenerative and regeneative
– mild multifocal purulent perivasculitis (M. gastrocnemius)
– histologically normal nervous tissue
Mild multifocal degenerative and regenerative changes of the striated muscle was found. A specific cause was not detected. It should be kept in mind, that in muscle pathology there may not be a strong correlation between histological changes and severity of the clinical symptoms.
Considering the purulent perivasculitis in the sample of the M.
gastrocnemius an inflammatory (possibly infectious) process in other
locations should be excluded clinically.
Signs for a polyneuritis have not been observed within the examined
I had to resign that the most likely cause of Scarlett’s condition was hypothyroidism and we started physiotherapy procedures.
Meanwhile, the patient’s condition has begun to improve. First Scarlett started to move her head better, started to lay on her chest and started eating by herself. The muscle tone start to improve.
40 days later
The day that Scarlett left the clinic.
Signalment: Dog, F, 5 y.o., German shepherd dog
History: Everything started with variable appetite. The dog came in the clinic for second opinion on 06.06.2019.
Colleague already took blood samples and there were no specific abnormalities.
-Hands off exam:
- Consciousness – abnormal
- Behavior – abnormal
- Seizers – no seizers
- Body posture – abnormal, head tilt, from time to time head turn, opisthotonus
- Gait – abnormal, symmetrical, general proprioceptive ataxia
-Hands on exam:
- Cranial nerves – vision, oculovestibular and menace is absent, contraction of the pupils is normal but dilatation is reduced, increased jaw tone, reduced gag reflex and reaction of the tongue.
- Postural reaction – proprioception and hopping are absent
- Spinal reflexes – absent withdrawal reflex on the left front legs, reduced on the right front leg.
Localization: Central vestibular
Differential diagnosis: Metabolic/Inflammatory/Neoplastic
I took blood samples to examine fT4 just to be sure that this is not hypothyroidism.
We discussed with the owner that if there is no abnormalities in thyroid hormones we will take and make some tests with CSF.
The level of fT4 was 1,60 pmol/ L (7,7 – 47,60 pmol/L)L
I started levothyroxine and after two intakes of the medication the result was:
The next few weeks the dog was not still in perfect condition, but there was improvement.
Conclusion: Hypothyroidism is often over diagnosed condition, but is also misdiagnosed metabolic disease with lots of different signs and different manifestation in every part in veterinary medicine.
Sofia city, Bulgaria
The radial nerve palsy is a pathology that is rarely seen in dogs, in comparison to cats, where it is more commonly seen, especially in young stray cats. The most commonly observed clinical picture in such patients includes paralysis of the antebrachial portion of the limb, the carpus, the manus and fingers. According to our personal observations, in about 25% of these patients the elbow’s neuro-muscular apparatus is also involved, in a different degree.
The patients demonstrate an external rotation of the antebrachial area in relation to the portion of the limb above the elbow.
The carpus and manus possess an additional and permanent external rotation in relation to the antebrachium, which causes the patients to use the rostral portion of the their carpus for stepping and weight bearing, which in turn inducts the formation of a chronical traumatic inflammatory proliferative granuloma in this area. For about a 25-45 days period, an impossible to overcome carpal hyperfelexion develops, to the point where the joint can no longer be returned to its physiological position, due to the shortening of the flexor muscle-tendon apparatus (see video 1 with cat Sonia 39 days after the trauma at https://youtu.be/SZoXfp8tMJ0 ).
A few therapeutic approaches are being advised for this pathologic condition worldwide: total limb amputation; stem cell therapy (with still controversial results); standard pancarpal arthrodesis (note that very often it is very difficult to execute procedure in the state of this disease and is almost always accompanied by a nonsatisfactory limb function end result).
None of the upper mentioned approaches for treatment of radial nerve palsy in cats, while trying to avoid limb amputation, was producing satisfying results in the patients with this problem, operated by our team. This is the reason we decided to test and implement a new “Dobro hrumvane modified pancarpal arthrodesis” procedure for the operative treatment of feline radial nerve palsy.
- Report patients base
Up to this moment, this modified by our team procedure has been done in 111 patients. In the first 11 patients we tried different but very similar to each other versions of the modification, and after patient 12 up to patient 111 (meaning exactly 100 patients) we were performing always one same version of the technique.
In 87 of these patients a follow-up postoperative monitoring for over one year has been performed (in 9 of them an approximately 5 year follow up was achieved, in 33 patients the follow up period was approximately 4 years etc.), in 11 patients the follow up period was between 4 months and one year and in 2 patients the follow up period was less than 4 months. In four of the operated patients, pre- or postoperative clinically relevant paralysis of the elbow region was also observed. As was mentioned earlier, 25% of feline radial nerve palsy patients demonstrate this (according to our observations in 23% of the patients it is already observed in the preoperative period and in other 2%, it develops a few weeks after the surgical intervention, with the reasons for that still being unclear). It should be noted that the majority of owners of patients with elbow area involvement preferred amputation over the experimental procedure.
- Surgical technique
The standard pancarpal arthrodesis general guidelines are being followed, but with the following modifications:
- Straight 11̊ inclination non locking hybrid pancarpal arthrodesis plate has been used (produced by Medimetal or Mikromed, delivered by VetWest). The plate contouring should be modified before the surgery and the inclination should become 21-22̊. Twisting of the distal portion of the plate internally in relation to the proximal portion of the plate is not recommended! For the fixation to the metacarpus 1.5 mm non locking screws were used (produced by Mikromed, delivered by VetWest) and for the fixation to the radius 2.0 mm non locking screws were used (produced by Mikromed, delivered by VetWest);
- The proximal (os carpi radiale et ulnare) and distal carpal bones are being completely removed, this being done with extreme caution not the traumatize the adjacent magistral structures (especially blood vessels), which are located on the palmar surface;
- The proximal ends of the metacarpal bones are being separated from one another;
- The fixation of the plate to the dorsal surface of the third metacarpal bone is achieved the same way as in the standard technique, using 1.5 mm thick and 6 mm long screws, but the fixation to the radius is not applied on its dorsal, but on its medial/mediocaudal edge/surface, using 2.0 mm screws. The screw hole on the plate which is intended for os carpi radiale (note that this bone is actually removed in the modified technique) is used for an additional 2.0 mm screw, placed in the distal radius. In other words, the whole metacarpal portion of the limb is being internally rotated around 85-95° (for the purpose of that an almost full blunt and careful separation of all soft tissues, including the magistral vessels and nerves in the distance between the carpus and the middle portion of the metacarpal bones, should be performed). After plating of the third metacarpal plate with four 1.5 mm non locking screws in neutral position the third metacarpal bone is being compressed to the radial distal This compression is easily achieved with the first screw, placed in the radius (not dorsal but medial/mediocaudal radial edge/surface – see below Xray picture Standard) thanks to the DC wholes of the plate types mentioned upper above. This screw is being inserted in the second 2.0 mm screw whole in distal to proximal direction, meaning the third plate hole in relation to the whole plate in proximal to distal direction. After that, 4 neutrally (not in compression mode) placed screws are applied to radial bone in the following order: the most distal hole, the most proximal hole, the second hole in proximal to distal direction, the third hole in proximal to distal direction. It is recommended that at least two of the screws in the distal radius engage the distal ulna too, so the distal portions of the two bones could eventually be pulled together – the screws could be numbers one and two or four and five from proximal to distal, this possibility could be estimated only intraoperativelly;
- With this technique it is easy and recommendable to use a significant amount of autograft material – recommendable due to the large gap that is being created. This autograft is readily available, considering the amount of bone that is being removed in the previous stages of the surgical technique;
- The final stage of the surgery includes almost full blunt separation of the skin from the underlying soft tissues in the designated area, along with skin plastic traction modification, which is intended to place the fifth finger in a more medio-cranial position. The skin sutures and respectively the skin incision should be placed in a position that is not exactly above the plate (eventually they plate and incision could be placed in a cross manner, but should not be on top of each other for their whole lenght). It is not necessary to perform tenodesis of the digital extensors or excision of some skin on the dorsal carpal area in orther to pull the fingers in extension. It shoud be noted that the upper mentioned skin traction used to “pull” the fifth finger in a more dorsal and medial direction (meaning that the fifth finger is placed adjasent to the dorsolateral, not solely lateral, surface of the fourth finger, under subtle tension that will not allow overlapping of the fifth finger) is extremely important because in some of the first patients, which underwent the still not perfected procedure, weeks to months after the surgery pressure necrosis developped in the fifth finger, which required further revison plastic surgeries.
- In patients that have a very wild temper and where it is not possible to achieve two week long cage rest, postoperative splint could be placed. If this is done, additional amount of cotton could be used to help achieve the upper mentioned mediocranial position of the fifth metacarpus and finger;
- NEO K-9 clinical formula is prescribed for a month and a two week long cage rest is done in more calm patients.
- C) Results – the last 100 cats (No 12 … No 111 made with identical technique) :
C1) 96 patients that did not have (according to our clinical opinion) involvement of the elbow region pre- or postoperatively:
– 95 patients with good limb geometry in stance and during walking, active involvement of the limb during walks and playing, owners completely content with the results 4 months up to 5 years after the surgery. 89 of these 95 patients had no postoperative complicatioons; 2 patients developed moderate postoperative infection that was easily treated; 2 patients demonstrated delayed healing of the surgical incision in the area above the plate (it took more than 5 weeks in both patients); 2 patients had delayed bone union, that took around 5 months to be completed;
– 1 patient demonstrated unsatisfactory to this point level of weigt bearing and limb usage during walk and play. It is understandable that the owner of this patient is not completely content with the results, but is unfortunately refusing implant removal and further diagnostic procedures;
– No cases with implant loosening, intra- or postoperative fracture, postoperative necrosis etc.;
C2) 4 patients with clinically relevant pre- or postoperative involvement and paralysis of the motor unit of the elbow joint:
– 1 patient without preoperative elbow problem, developed such around a month after the surgical intervetion and the problem was accompanied by the development of an additional low grade external rotation of the antebrachium in relation to the limb portion above the elbow. The main problem was presented by progressive loss of support of the ebow joint in extension during stance, which lead to the inability of the limb to support the body during weight bearing. The problem was resolved after a two week long active rehabilitation and machine physiotherapy and application of a light splint, which is suporrting (but not blocking) the elbow.
– 1 patient (cat named Trun) with preoperative paralysis of the elbow joint, but accompanied by almost complete ankylosis of the elbow joint (only 15% of the normal range of motion was preserved, especially the extension was blocked) – see below the post-op pictures of cat Trun
Although there was a serious accompanying problem, months after the surgery the owners are completely satisfied with the result. The patient is using the limb with no limitations during play, almost no limitations while running and with some limitations while walking – that last limitation is probably due to the constant flexed position of the elbow, which is exceeding the normal flexion angle of an elbow joint during walk, thus the animal is placing the shoulder of the affected limb under the level of the shoulder of the unaffected limb, during weight bearing (see video with cat Trun approx 3 months post-op at https://youtu.be/N9scMppZeyo ). The owners do not report signs of pain. Even though it is not right to make conclusions only on the basis of a single patient, this case gives us hope that patients with radial nerve palsy in combination with complete or partial elbow joint ankylosis have the chance to avoid amputation of the limb.
– 1 patient with partial preoperative paralysis of the elbow joint which became more severe (around 50%) month after the surgery: the bones in the arthrodesis region achieved complete healing, but the elbow joint loses support during weight bearing, thus the animal is placing the shoulder of the affected limb under the level of the shoulder of the unaffected limb, during weight bearing. Due to this the ptient is weight bearing the limb not on its pads, but rather on the carpal palmar angle surface. Because of that a chronic nonhealing skin lesion developed in this area over the time, which is intermitently bleeding. Up to this point, the owners are content with the result and do not wish to start rehabilitation or agree to a revision surgery, but for our team this result is unsatisfactory and it requires additional surgical and/or physiotrepautical intervention;
– 1 patient (Doxy) wtihout preoperative involvement and paralysis of the elbow, which developed a progressive clinically relevant paralysis of the elbow a few weeks after surgery. This led not only to loss of support of the elbow joint during weight bearing, but also to constant progressing additional rotation of the antebrachium in relation to the humeral area.
This rotation made the patient bear weight on the lateral surface of the carpal angle, developing a skin lesion there. This postoperative elbow joint paralysis did not resolve after a rehabilitation course. In order to correct the problem an elbow arthrodesis was performed, but not in a standard way. A “double-modified” elbow arthrodesis was performed: the boomerang plate produced by Mikromed and supplied by VetWest was placed on the lateral surface instead of the medial. Also, the antebrachial region was rotated 18 degrees internally, in relation to the humerus. We recommend very torough preoperative preparation: the execution of the technique is quite challenging, because the compression must be maintained and in the same time the “locking” of the anconeal process in the humeral fossa must be overcome, along with the congruency of the other ulnar structures and their corresponding radial structures – see below post-op X-ray pictures of cat Doxy after the second surgery, the elbow modified arthrodesis:
It can be seen that the plating is on the lateral surface of the radius distally and on the laterocranial surface of the humerus proximally.
Only a few hours after the surgery, the patient demonstrated excellent, pain free limb usage, with very good limb geometry and lack of difference in the level of the two shoulder joints during weight bearing. In the following days the patient started using the limb for playing too. At this point, 3-4 months after surgery, the patient is demonstrating completely satifying results (see video with cat Doxy approx 4 months post-op at https://youtu.be/X_rFEgrZink ). There are no signs of malunion, infection or other types of complications. The muscle mass in the shoulder area of the operated limb is similar to that of the non operated limb. Even if it is based just on one patient, the result of this case gives us some hope for surgical resolution for patients with modified or standard carpal arthrodesis, which have an acompanying or later develop severe elbow pathology of nonakylotic kind, as we know that the combination of carpal and elbow arthrodesis is not recommended in the known sources. For this patient especially we have an additional recommendation:
1) The first recommendation that is applied to all 111 operated patients – considering that it is a patient with a paralysed limb it should live on a non- smooth surface (but also not on an abrasive one). On a slippery surface patients with Dobro hrumvane arthrodesis step with mild slipping which combined with the lack of sensitivity could cause in longer period skin lesion (see Video 2 with cat Zhivka approx 5 weeks post-op at https://youtu.be/hKKjmO9yWdI ).
2) Additional recommendation especially for Doxy: the patient has two joints that underwent arthodesis, which means that a stress point is being created between the two plates, which in turn creates a significant risk for further fractures. This risk is further amplified by the fact that the arthrodesis procedures are reducing the shock absorbing function of the joints. Considering all of the mentioned above, the patient should live in an enviornment that lacks the risk of creation of serious vertical vector forces (such as jumping to or from high places). It should be noted that Doxy did exactly that, many times after surgery and no problem occured, but it is still highly not recommended.
The 100 clinical cases, with patients that underwent a similar modified pancarpal Dobro hrumvane arthrodesis procedure for the treatment of feline radial nerve palsy demonstrate a constant and satisfying result with very good return to function of the limb, pain free, with no discomfort. No following complications, including long-term ones are being observed and there is a very high level of owner satisfaction. We recommend this surgical technique and we would be glad to recieve feedback afer the completion of the procedure, either in the algorithm recommended by us, or with any additional modifications.
Even when the rotation of the metacarpal area in comparison to the antebrachial area is not 85-95 degrees the patients use the leg and the owners are satisfied but the leg geometry is in our opinion not good looking. Cat number 11, the last before the standartized 100 patients chain, named Hari is such a case, the rotation was 78-80 %, the operation was made approximately 5 years ago. As you can see at the videos made 4 years post-op the patient uses the left operated leg even during acrobatic jumping (see below picture Hari)
and active playing (see video Hari 4 years after surgery at https://youtu.be/SfhzUtLr9ig ).
- E) Post scriptum
A few years ago we presented the technique and its results, based on a few dozens of cases, on a VOG\BAVOT event. Ever since, a few colleagues from the Balkan region have sent us feedback with very encouraging results, after using the technique. One of them was our inconsolable friend, colleague and inspirator, D-r V. Vasilev, whose memmory and collosal contribution to the development of the veterinary meidicine in Bulgaria we would like to honor in the end of this report.
Sofia The Orthopedic department of
March 2019 “Dobro hrumvane!” veterinary clinics
Blue Cross Veterinary Hospital
A 4 months old Labrador retriever was presented at the BlueCross Veterinary Hospital in Sofia, Bulgaria, with the owner complaining about painful episodes after touching the head of the animal.
Clinical examination: the dog is in a good clinical stage, no pathological heart or lung sounds.
The temperature was 39,5 C. No abdominal pain or other abnormalities.
The palpation of the skull was painful for the dog, there was slight dome shape of the cranium. The masseter muscles were atrophied. After palpation of the mandibula it was noted that the lower jaw of this dog looked enlarged. Pic 1
Considering the age, breed and the affection of the specific bones, the following list of differential diagnosis was made:
- Craniomandibular osteopathy
- Calvarial Hyperosthosis
We took a blood sample for CBC and biochemistry analysis.
On the CBC there was a slight decrease of the RBC – 5,36 (5.5- 8.5 x10/12/L) but this could be normal for younger animals.
On the biochemistry there was a slight decrease of the Total protein – 49 (51- 78) g/L and Albumin – 20(26- 41) g/L. Everything else was WNL.
The patient was sent for CT of the head to search for additional characteristics of the bones of the head and confirm my suspicion about the disease. We put an injection of NSAID for the pain until the test was done.
On the CT we discovered symmetrical bone proliferation of the rami of the mandubule and bone thickening of the calvarium of the animal. No underlying bone lysis was noted. Fortunately, till this moment affection of the temporomandibular joints was not discovered, but it is possible that this could happen during the next months.
There were not clear signs of neoplastic process or osteomyelitis. As a result, considering the information that we had, a diagnosis of craniomandibular osteopathy was made.
Craniomandibular osteopathy is a non neoplastic proliferative bone disease affecting immature dogs.
Usually the clinical signs start between 3 and 8 months of age. Common clinical presentation is pain episodes, fever, trouble chewing food, drooling and in more advanced cases – inability to open the mouth and eat. The etiology of this disease is unknown.
The first written description of CMO appeared in 1958.(9) It was described in five West Highland white terriers affected within a 2-year period. The most common breeds that are affected are West Highland white Terrier, Scottish Terrier, Cairn Terrier. The disease is described in other breeds – in Labradors, Boxers, Great Dane and a few more.
It is believed that this could be an inherited disease (autosomal recessive inheritance pattern) and as such it is advised for such animals to be neutered.
Commonly the affected dogs have bilaterally symmetrical enlarged mandibles and tympanic bulles, and affection of other bones of the calvarium. In severe cases those structures could fuse and this will lead to decreased range of motion of the temporomandibular joint. On examination, the temporal and masseter muscles may be atrophied.
In advanced cases, the diagnosis of craniomandibular osteopathy can be done with good positioned x-rays of the head of the animal. The advance imaging techniques, such as CT or MRI, improve the visualization and confirm the extension of the process.
On x- ray or CT increased irregular bone density is commonly observed – symmetrical periosteal proliferation, in most of the cases primary affection of the mandibules- 84%; tymplanic bulles – 51% and in some of the cases bones of the calvarium -13%.
The treatment plan is symptomatic with painkillers and anti-inflammatory drugs – commonly used drugs are NSAID and Steoids. Such drugs are needed during pain episodes and fever. Placement of an esophagostomy or gastrostomy feeding tube may be considered in patients that have difficulty eating and their nutritional requirements are not being met. Soft or liquefied food may be easier for some patients to eat. A high protein, high caloric food should be offered in order to meet nutritional needs.
Surgery of the bone proliferated tissues is not helpful in those cases.
The prognosis for these patients depends of the extent of progression of the disease. In those cases where a severe bone proliferation develops, the result is fusion of the temporomandibular joint and the prognosis is poor. Most of those dogs are euthanized because of the extent of the disease. It has been a common observation that when the affected dog is approximately 11 to 13 months of age, the disease may become self-limiting. The growth of abnormal bone slows, often regresses, and sometimes recedes completely. This period of self-limitation coincides with the time of completion of regular endochondral bone growth and ossification.
Our patient felt great after one injection of meloxicam. He is feeling active and has no signs of pain and temperature. Unfortunately, we cannot say whether his condition will progress to the extent to affect the temporomandibular joints and lead to inability to open its mouth.
The owner will return the dog to the breeder. It was advised to watch the dog for any additional signs and painkillers were prescribed.
Dr Svetoslav Penchev
United Veterinary Clinic
Case is about a 6 months , male cocker spaniel named Michael.Michael was brought in the clinic from another city in very bad candition.The owners report for a trauma in cervical region.Radiography and neurological examinations were made. Results revealed –Tetraplegie and atalnto-axial instability.It was made a CBCT on cervical region.The image show C2-Fracture .
It was maked a surgary to stabilize cervical spine. Ten days after surgery Michael starts moving the pelvic limbs first and tries to stand on them. Twenty one days after surgary Micheal start to moving and thoracic limb , but have ataxia and destroys proprioception on his four leg. Michael`s recovery begin first with the hind limbs and then with the thoracic limbs .In human literature, the symptom in which the thoracic limb is in a dysfunctional state with minimal to no deficit in the pelvic limbs has been referred to as CCS (Central Cord Syndrome ). The spinal cords that travel to the pelvic limbs are minimally affected because the lesion is centralized in the cervical region, which only affects the thoracic limbs. In general, CCS has a good prognosis for functional recovery and its common etiology is traumatic disease in human medicine. CCS treatments with nonsurgical management include cervical spine restriction with a neck collar, rehabilitation followed by physical therapy and occupational therapy. Surgical management is provided for patients who cannot be treated by conservative management alone.
Transplantation of ipsilateral canine ulna as a vascularized bone graft for treatment of distal radial osteosarcoma
Corresponding author :
Dr. Vladislav Zlatinov,
Central Veterinary Clinic
Chavdar Mutafov str, 25 B, Sofia, Bulgaria
This case report describes the successful use of a vascularized cortical autograft from the ipsilateral ulna in limb-sparing surgery for the treatment of distal radial osteosarcoma. A pancarpal arthrodesis with two orthogonal plates was performed to stabilize the site. No implant failure and local tumor recurrence were observed in the 6 months post operative period. Excellent limb function was achieved within 6 weeks after surgery; no external support (coaptation) were used during the post operative period. Excellent perceived quality recovery, was reported by the dog’s owners, compared to their preliminary outcome expectations.
Osteosarcoma (OSA) is the most common primary bone tumor in dogs, most commonly affecting the distal radius. Current treatment protocols-Fig.1 are based on a combination of surgery (limb amputation or limb sparing surgery) and adjuvant chemotherapy. Palliative therapies like- Stereotactic radiation or Percutaneous
Cementoplasty therapy are rarely applied with limited success 1,2.
Recently, numerous publications suggest that the Limb-sparing surgery is a viable alternative to limb amputation in selected cases, especially indicated if there is pre-existing orthopedic or neurological disease or if owners are resistant to limb amputation 3,4,5,6.
Limb- sparing consists of removing the segment of bone involving the primary tumor and using internal or external fixation to the remaining bones with or without segmental bone replacement, resulting in a salvaged functional limb 7. Limb- salvage procedures
have been described in the distal aspect of the radius, proximal humerus, distal tibia, and proximal femur in dogs with OSA, but the salvage surgery of the distal aspect of the radius has produced the most favorable results. This is mainly because pancarpal arthrodesis is well tolerated by dogs, not like fusion of other joints. Importantly – the prognosis for survival is the same with amputation or limb- sparing, unless an infection is present, in which case the average survival is prolonged.
Candidates for limb sparing
Good surgical candidates are dogs with OSA confined to the bone, with minimal extension into adjacent soft tissue and involving less than 50% of the bone length. The extent of bone involvement is most accurately determined by using computed tomography and is overestimated by radiography, nuclear scintigraphy, and magnetic resonance imaging 8. Pathologic fracture is a relative contraindication for limb-sparing because of tumor seeding into adjacent soft tissue, although the risk of local tumor recurrence can be reduced by use of preoperative chemotherapy or radiation therapy.
Limb sparing techniques
Historically, the most commonly performed limb sparing technique for the distal radial site involved the use of an allograft (donor from an individual of the same species) to replace the bone defect created by segmental bone excision 9- Fig.2. Although the limb function is good to excellent in about 80% of dogs with the allograft technique, the complication rate is substantial. The most common complications include infection, implant related problems, and local recurrence. Infection rate is reported to be up to 60%, implant failure in up to 50% as well. Even more, there are practicality issues for the regular application of the allograft technique- time consuming and costly maintenance of a bone bank. Recently, there is a new alternative for graft purchasing from a commercial source on a case by case basis.
It’s not surprising that alternative limb-sparing methods are being investigated. Reported grafting techniques include pasteurized/ irradiated autografts, endoprosthesis, vascularized ulnar transposition graft (roll-over technqique), free microvascular ulnar autograft.
Nevertheless the technical evolution of the available techniques, all of them are still often associated with a high complication rate including infection, construct failure, and tumor recurrence. The longitudinal or transverse bone transport osteogenesis has the advantages to lower the aforementioned complications but still have limitation for routine implementation in the practice 10, 11.
The advantages and disadvantages of the recent innovative techniques are shortly summarized below.
The most prominent advantage of the endoprosthesis limb salvage (Fig.3) is the simplicity compared to the other grafting techniques; consequently it is time-saving. Decreasing the surgery time may suggest lower infection ration. Unfortunately this was not proved by the clinical experience with the currently commercially available endoprosthesis.
A recent study 4, comparing the results of Cortical Allograft and Endoprosthesis techniques, suggested surgical infection of 60 and 55% of the cases, respectively. The use of a large volume of implants and foreign material has been proposed as a cause. More over in the same study, long term implant failure occurred in 40% of the treated dogs.
A positive remark in the paper is the good (subjectively) limb function, reported in the stable phases or in non-complicated cases.
A more biologic friendly technique- ulnar roll-over – Fig.4 was resently reported with good results, despite limb shortening of up to 24 % 3,12,13. The distal ulna is osteotomized, rolled into the radial defect, and secured with a bone plate and screws. With this technique the preservation of the caudal interosseous artery and vein and a cuff of the deep digital flexor, abductor pollicis longus, and pronator quadratus muscles are important for maintaining viability of the transplanted ulna.
Theoretically, using a vascularized bone graft could reduce the gross incidence of complications compared to an allografts or endoprothesis. Vascularized bone is more resistant to infections, to the extent that vascularized cortical autografts have been used to treat osteomyelitis. Also the use of a viable graft may preserve biomechanical properties over allografts. Whereas the allograft may resorb and become weaker over time, the ulnar graft may maintain its physical properties or even hypertrophy and healing with the host bones.
However, the statistics reports are controversial, with no clear proof for substantially better outcomes. One study shows no statistically different infection (45%) and implant failure (55%) ratio. Probably the presence of a viable graft does not address all other factors predisposing to infection (poor soft tissue coverage, immunosuppression from neoplasia and chemotherapy, and use of orthopedic implants). The other complication problem- implant failure, sounds as a surgeon’s skills dependent issue. For example one of the major complication in the mentioned study has been fracture of the remaining radius in cases of great length resection (>57%), which could be just consequence of suboptimal plate length or screws number and distribution.
Importantly, the roll-over technique demands sufficient length of the distal ulna to be preserved, but local recurrence was not increased compared to other limb- sparing techniques.
Microvascular anastomosed bone transfer was used in the presented case. This is a routine procedure in the limb sparing surgeries in human patient, but rarely applied technique in veterinary medicine, nevertheless, the vascular supply of the distal ulna has been , studied, described and successfully used experimentally and clinically 14,15.
In this technique, a more substantial middiaphysis segment of the ipsilateral ulna, with its source artery and vein (the common interosseous) is harvested and transpositioned, with a blood supply restored by vascular anastomosis to a neighboring artery and vein, once the graft is in its new position. The surgical technique is described further in the text. The concept is the same as the ulnar roll-over but, with the advantages of stronger cortical ulnar graft used, more mobile graft and a chance for full distal ulnar resection. The disadvantages of this procedure are the need for a specially trained and equipped microvascular team and the prolonged surgical time.
Longitudinal bone transport osteogenesis
This is a specific application of distraction osteogenesis, which has been used successfully in dogs for replacement of large segmental defects of the distal aspect of the radius and tibia after tumor resection. This is a process whereby healthy, detached bone segment is sequentially moved across an adjacent segmental osseous defect forming new regenerate bone in the distraction gap -Fig.5.The regenerate bone is highly vascular and resistant to infection.
The results following the procedure have been very encouraging, with good orthopedic function and no reported infections. Disadvantages of the bone transport osteogenesis procedure is the significant amount of time required to fill the defect after tumor removal (up to 7 months). This often leads to owner compliance issues (distracting the apparatus two to four times per day), also pin-tract drainage and loosening, difficulty in docking the intercalary bone onto the radial carpal bone.
A recent modification –Transverse Ulnar Bone Transport Osteogenesis, has been reported 16- Fig.6. The technique substantially decrease distraction times. In one case report, distraction of the ulnar transport segment across the 84 mm longitudinal segmental radial defect, was completed in 23 days.
A 9-year-old female Rottweiler dog (43 kg) was referred to our practice with a 3- weeks history of left forelimb lameness with an gradual onset and an unknown origin. The dog was been previously prescribed NSAIDs with temporary effect. During our examination we found weight-bearing lameness II/V. Physical and orthopedic examination revealed distal radial swelling on the left forelimb, with pain on extension of the carpal joint.
Orthogonal radiographs were achieved, revealing vast osteolytic (relatively smooth margins) area in the distal radius, with no apparent lesions in the distal ulna- Fig.7
Based on the history, signalment, lesion location, and radiographic findings, a primary bone tumor was suspected.
No abnormalities were detected on preoperative 3-view thoracic radiographs, abdominal ultrasound, echocardiography, and blood tests- Fig.8. The Alkaline Phosphatase (AP) value was 195 U/L- in the upper limit but still within the reference range for the breed.
Treatment options were discussed with the owners:
-conservative palliative treatment
-amputation and chemotherapy
-limb-sparing surgery in conjunction with chemotherapy;
The owners chose the last course of treatment but insisted on preoperative histologic confirmation of the suspected diagnosis.
After short anesthesia and minimal invasive approach, tissue biopsy sample was retrieved and send for analysis. Ten day later the the suspicious of osteosarcoma neoplasia was confirmed. The histologist comments were: moderately aggressive OSA with low mitotic figures. Meanwhile the dog showed acute lameness deterioration, related to a pathological fracture of the cranio-distal cortex of the radius, following the biopsy procedure- Fig.9.
A limb sparing procedure (roll-over vs. free vascularized) grafting was planned.
Twenty minutes before the skin incision high segmental epidural analgesia wad accomplished at the level of T11, infusing 2 ml of 0,25 % Levobupivacian solution and positioning the patient in left lateral recumbency for 10 minutes- Fig. 10.
For the surgical intervention, the dog was positioned in sternal recumbency- Fig 11. , facilitating a dorsal approach to the radius and carpus. Careful tissue examination was done during the sharp dissection of the distal soft tissues. Caudally, the tumor was closely attached to the distal ulna. Thus, the tumor was not dissected caudally to avoid contamination. A decision for a more extending distal ulnar resection was made. This prevented the option for roll-over technique more advanced free vascularized transfer was prepared.
The extensor carpi radialis muscle was transected proximal and distal to the tumor; the common and lateral digital extensor tendons were spared. An oscillating saw was used in both radial and ulnar osteotomies. The level of the transverse osteotomy of the radius, 2 cm proximal to the tumor, was determined on radiographs and confirmed appropriately intraoperatively. The ulna was osteotomized at lower level, just over the overlapping zone with the radius. The radius was disarticulated at the antebrachiocarpal joint and the tumor removed en bloc with the distal ulna. The length of the resected radial segment was 10 cm, including the 2-cm free margins (this represented 45% of the total radial length). The whole radio-ulnar segment was stored in 10 % formalin solution for later histologic analysis-Fig.12 and 13
After tumor removal the limb sparing was continued with cartilage debridement from the carpal and metacarpal bones , accomplished by using a speed burr drill; several penetrating drill holes were created in dorsal surface of the radial carpal bone.
The resected radial bone segment was measured and a second ulnar osteotomy performed proximally using a separate blade to match the length of removed radial bone minus 1,5 cm. The proximal ulnar osteotomy was performed above the level of the radial osteotomy while identifying and carefully dissecting the caudal interosseous artery and vein.The last were a-traumatically clamped and transected as proximal as possible, preserving as much as possible of the vessel length.The muscle attachments of the abductor pollicis longus, ulnar head of the deep digital flexor, and pronator quadratus were kept intact onto the periosteum of the distal aspect of the ulna.
The ulnar graft was transposed into the radial defect and the proximal end of the common interosseal artery (<2 mm) was anastomosed to a distal branch of the median artery. The anastomosis was accomplished with the use of magnification (10x) with surgical microscope and fine jewelers forceps- Fig.14 and 15. General principles of end-to-end vascular anastomosis were followed- atraumatic handling, distance of 0,5- 1 mm from the vascular wound’s edge, the regular suture distance, etc. Five interrupted sutures (8-0 nylon) were used to seal the anastomosis. The total ischemic time of the bone graft was about 60 minutes.
The microanastomosis success was confirmed by identification of a active blood flow present in the graft’s tissues and the distal end of the interosseal artery (video 1 ). The corresponding vein was not anastomosed, but its end was left free in the surrounding soft tissues. The distal artery ending was ligated.
After the anastomosis, the procedure was finished by stabilization of the bone graft by long plate, engaging from the distal metacarpal bones to the proximal radius, on the cranio-dorsal surface. We used hybrid 4,5 mm plate (Mikromed, human series) allowing fixation with 4,5 mm screw proximally, 3,5 mm in the middle area (free graft) and divergent 2,7 mm screws in the III and IV metacarpal bones. A second orthogonal plate 3,5 mm reconstructive locking (Mikromed) was applied laterally, fixating the proximal radius to the fifth metacarpal bone- Fig.16 and 17. Copious cancellous bone graft (from proximal humerus) was retrieved and stacked at the level of all osteotomy gaps.
After copious wound lavage and before closing of the surgical wound, the implants were covered by Gentamycin impreganted bovine collagen sponges (Gentacoll- resorb). The goal of the last was infection prevention. A soaker catheter was also inserted along the full length of the surgical wound. Subcutaneous tissue and skin were closed routinely. After skin suturing, the leg was bandaged with modified Robert -Jones bandage for the next 12 hours. The soaker catheter was attached to elastomeric pump, delivering 1 % Lidocain solution – 5 ml/h, for the next 3 days.
Post operative care
Postoperative analgesia consisted of: local Lidocain flash block delivery by the elastomeric pump (36 h) , Butorphanol (0.3 mg/kg, every 6 h, i.v.) and meloxicam (0.1 mg/kg /24h ,s.c.).
Cryotherapy (frizzed towels compresses) was applied every 4 hours for the next 48 h- Fig. 18
Cephazolin (20 mg/kg/8 h, i.v.) was applied for 3 days post op.
On the third post operative day -the dog was discharged, with oral Cimalgex (Cimicoxib, 2 mg/kg/day) for 14 days. Oral amoxicilin clavulonic acid (12,5 mg/kg/12h) was administered for 2 weeks and exercise was restricted to short walks on a leash for 12 weeks. The dog was re-examined regularly- every 14 days, including the visits for the chemotherapy sessions.
The histopathological diagnosis of the excised bone confirmed a grade II fibroblastic osteosarcoma (OSA)– Fig. 19. Surgical resection was considered complete with no evidence of neoplasia at joint compartment.
A single agent protocol -carboplatin (300 mg/m2)- Fig. 20, was planned and applied every 3 wk for a total of 5 treatments. The first treatment was started 2 weeks after surgery. A CBC was taken 2 weeks after and just before each carboplatin administration; serum biochemistry was performed every 2 months. There was no evidence of gastrointestinal upset, renal failure or myelosupression after chemotherapy. The AP levels were always in the reference range.
Clinical recovery and Follow up
Lameness progressively improved from toe-touching (one day after surgery) to full weight-bearing with only slightl visible lameness- 6 weeks post op. No external coaptation was applied during the recovery period- Fig.21, Video 2- 3.
Six months post op the limb function was appreciated as excellent, without any significant changes on limb palpation- Fig.22. Video 4. Orthogonal radiographs were taken, showing proximal bone fusion; distally the bone was superimposed by the lateral plate. No signs of construct failure were observed. A decision for dynamisation was made and the lateral plate was removed, revealing radiographically the bony structure under it. It showed good bone density and excellent graft fusion (primary), proximally and distally. Further segment hypertrophy is expected by the increased load sharing.
The limb sparing surgery could be a viable option for treating distal radial OSA in properly selected cases. With the innovative alternatives, the widely accepted approach to canine OSA – limb amputation treatment, should not be applied as “default treatment” in each case. Case to case individual approach may provide the pets and their owners more fare attitude. Excellent functional results of the limb may be achieved by a complex (but single stage) surgical segment resection and appropriate bone reconstruction and rigid fixation. The use of free vascularized bone graft is a manageable option and an alternative to ulnar-roll over in cases of distal ulnar tumor engagement or vast radial segments resection, where solid vascular bone grafting is demanded.